There is a request for security control using a so-called USB (Universal Serial Bus) (registered trademark, hereinafter omitted) security function of a USB hub. The USB security function prevents individual USB-connected devices from being used by other users.
Generally, the number of USB ports tends to decrease as the number of chips is reduced. Therefore, a built-in USB hub controller may be used to satisfy the number of external USB ports and the number of built-in USB device connections. There is also a request for the support of the USB security function for this case.
According to the existing USB security function on USB ports, for example, a port Enable/Disable register is set disable for each USB port located in a USB host controller, so that the USB security function are obtained for each port (on the other hand, external USB ports may be set collectively).
On the other hand, since downstream ports of the USB hub are made disable not individually but collectively, flexible security control may not be performed.